Can you please let me know which specification is written on the power adapter? because on other kind of router they need 9Vdc and/or 1A. Maybe the wr-703n needs lower Vdc and current, and so it can work also with arduino.
So given that I need an axternal antenna, I looked around but I found only router that need more Voltage than 5Vdc or a lot of current, more than the 600mA that arduino can gives.
Bye Ste